The invention relates to nuclear medicine, and more particularly relates nuclear medicine studies of patient organs, such as the heart. In its most immediate sense, the invention relates to proper positioning of a patient in nuclear medicine studies of patient organs.
In some nuclear medicine studies, such as bone scans, it is easy to properly position a patient with respect to the detector of a scintillation camera. However, in other studies, particularly studies of organs such as the heart, such proper positioning is difficult because many relevant factors (e.g. orientation of the heart within the patient's body, size of the various portions of the heart) are not known before the study is commenced. In these latter instances, a nuclear medicine study is usually commenced by positioning the detector of the scintillation camera in approximately the correct orientation, verifying the correctness of the position originally selected, and adjusting the position as necessary. The verification step is usually carried out by viewing a persistence image of the Region Of Interest (ROI) on the camera display.
There are two major disadvantages to this approach. First, when using a focussing collimator, it can be difficult for a technician to identify the anatomic feature of interest (for example, the patient's left ventricle) because its appearance can be quite distorted by the focussing scheme. Second, even if the anatomic feature of interest is identified, the positioning is not highly repeatable. Thus, for example, in cardiac myocardial perfusion tests, it is advantageous to conduct a first study with the patient at Zest and a second study after stressing the patient. The patient should be in the same position in both studies. If the location of e.g. the heart within the ROI is only known in a general way, the patient's position during the second study will not precisely replicate the patient's position during the first study.
It would be advantageous to help a technician identify an anatomic feature of interest, even when the feature appears in a distorted manner because a focussing collimator is being used to conduct the study.
It would also be advantageous to provide method and apparatus which would make patient positioning more repeatable.
Therefore, one object of the invention is to provide method and apparatus which will help a technician identify an anatomic feature of interest, even when the feature is displayed in a distorted form.
Another object of the invention is to provide method and apparatus which makes patient positioning more repeatable.
Still a further object is, in general, to improve on known methods and apparatus in nuclear medicine.
In accordance with the present invention, the camera is set up at an initial position and an image (advantageously a persistence image) is acquired. After a predetermined time, the data in the image is computer-analyzed in real time in accordance with the invention disclosed and claimed in the above referenced parent patent application, and a set of position-defining anatomic landmarks of interest (e.g. the left ventricular cardiac muscles of the heart) are thereby identified. (At least two such landmarks are necessary, in order to infer camera position.) A plot of such landmarks is then generated by the computer and the plot is then superimposed upon the part of the persistence image to which the plot relates.
This permits the technician to immediately identify the significant portion of the image and to center (or otherwise locate) that portion on the display. Alternatively, the positioning of the significant portion of the image can be detected by the computer and the technician advised of advantageous adjustments which might be made to the position of the patient and/or the camera detector.